CODEWITHSUNDEEP
dockerdockerfile
Dmitrij Kultasev
Dmitrij Kultasev

Reputation: 5787

Define variable from variable in the .env environment file with Dockerfile

I can use --env-file /path/to/.env to define variables. Is there a way to define variable from previously defined variable in the same file? Example:

SOME_USER=good_user
ROOT_USER=$SOME_USER

Upvotes: 1

Views: 313

Answers (1)

Peter Badida
Peter Badida

Reputation: 12199

As far as I know, it's only a simple list of values, nothing special such as templating or expansion and it's even broken for quotes so e.g. VAR="test" will be actually a value of "test" instead of test.

The documentation also doesn't mention anything, or at least explicitly.

... simple (non-array) environment variables ...

... This file should use the syntax <variable>=value (which sets the variable to the given value) or <variable> (which takes the value from the local environment), and # for comments. ...

$ cat file.env 
VAR=one
VAR2=$VAR
VAR3=${VAR}

$ docker run -it --env-file file.env busybox env | grep VAR
VAR=one
VAR2=$VAR
VAR3=${VAR}

Upvotes: 1

Related Questions